Explain whether or not you would expect any difference in the best$-$case and worst$-$case complexities of your function longest$\_$common$\_$substring Analyse the worst$-$case complexity of your function. You may find it convenient to define L $=|$ left $|$ and R $=$ right $|$ and to express the complexity interms of those values. We have used uppercase letters to avoid confusing lowercase $\text{'}1\text{'}$ with other characters.You should use Big$-$Theta notation $($Section $2\mathrm{.}7)$ or Big$-$Oh notation $($Section $13\mathrm{.}3\mathrm{.}3)$ as appropriate. Complexity of sequence operations $($which applies to strings$)$ is given in Section $4\mathrm{.}9\mathrm{.}1.$